Electric switch.



H. F. STRTTN.

` ELEcTmc SWITCH;

APPLCATlON .ULEB )ULY 27, HH.

atented Apr. 6, 1915.

2 SHEETS-SHEET 1.

ATTORNEY {NVENTOR QH. F. STRATTON.

ELECTRIC SWITCH. APPLICATION FILED JULY 21. 19H.

Patented Apr; 6, 1915.1

2 sums-ann 2.

' INVENTOR ATTORNEY sTAzrEs PATENT- onirica. i f,

nanny nstrnnrron, or CLEVELAND, cino, AssIeuon 'ro mansnncrnicconrnotiinn i.; A311) MnNUFnCmnRING COMPANY, oF CLEVELAND,011.10, A CQRPORATIQN or OHIO.

' lELECTRIC SWITCH.

Tf, all whom t ,may concern `Be itkuownthat I, l-IARRYF. STizA'r'ron,

alcitizen'of the United States, residingat Cleveland, in thel county ofCuyahoga and Stateof Ohio, have invented new and useful Improvements inElectric Switches,-` of Which the following? is a speciiication.

l My.` invention ,relates to magneticallyoperated switches forcontrolling the flow of current in alternating currentmotors. I

show these switches `employed ina Yccn- -fg troller by which analternating current motol-,may be started andzbrought up -to speed by"rautomatically cutting resistance ,out of the secondary circuit-of themotor.. l make use of magnetically-operated switches, each 'of whoseoperatingiwindings Vis connected in serieswith the secondary circuit andshortcircuited on closure of the switch contacts.A

Iprovide `for each switch a holding, or

, maintaining magnet which is excited from the primary circuit and doesnot necessarily a'idfinl operating thc switch, but is merely used tohold the switch `closed after it has operated. vThe operating windingbeing in circuit only While the switch is being actuated, its magneticcircuit or frame does not need to be laminated. The 'holding magnet'needs` to -be only strong enough to hold the switchpclosed, andtherefore, by la proper construction of parts the force it must exertcan be made much lsmaller than would; be required: -or operating theswitch through its whole movement. I prefer also to soconstruct'the'switch that the pull lof the holding magnet is multipliedthrough a lever mechanism thereby reducing thesize of thehold- 'ing`magnet and the amount of current required 'or exciting it. v` Since theholding magnet is energized during the whole time that the controller isin service, its magnetic circuit should be laminated, or, at least, thatpart which is embraced by the winding.

I consider a controller employing a switch constructed in such a manneras )ust described, which has an. operated winding adapted to beconnected in circuit only ya short-period, its magneticcircuit being notlaminated, and a holding 'magnet of small Siae-:with more-lor less ofitsmagnetic circuit llafrninated. more desirable than the usual typeffofailtvrnatingcurrent switch with a single winding which must be largeenough to operate the switch and hold it closed. The

latter .type of` s witchlisv i usually constructed with ltoggle,)ointsand spring contact de- Vices which are objectionable on account ofthe large number oif-small parts required .for-each switch.l

ln order ,tomore fully describe my invention I will referto theaccompanying drawings, in which# Figure l 1s a vertical section of aswitch,

constructed in accordance with my inven- Specification of LettersPatent` Ptnted A151215; 5.A Application mea Iuiyev, 1911A. serialno.640,855. f y l insulating support S2 andcontaining the ,f

winding S3, which has an axial opening. In the upper lpart of thisopening is the steel plug S4 provided with the liange S5 resting on theframe S. The coil-holding sleeve S6 surrounds the upper end of the plugand is screwed. into the top of the frame S. The

steelplunger S7 is seated inthe axial opening in the coil 4below theplug S and is connected to the lower end of the non-magnetic rod S8,which extends Vup' through .the plug S4 and carries the contact-plateholderS9 at its upper end.V S1o is the contact-plate on the top oil theholder i. 9, and is arrangedto'conneet together the three brushes S11,S12, S18, supported by suitable fixed contact holders, of which oneonly, marked S14, is shown.l S1, is an adjustable sleeve olf-magneticmaterial which surrounds the reduced lower end of the plunger S7 and isscrewed into the lower portion of the frame S. The nut S16 Working onthe sleeve and bearing against the bottom of the frame serves as alock-nut for vpredetermined value, the plunger S7 yis caused to remainin Yits lowered or .unactuated position, but when the current is loweredto the predetermined value,the plunger is caused to rise and carrv thecontact plate S into engagement with the brushes S11, S12, and S1 Iplace below the switch just described the hollow casting S17 whichcontains the holding, or maintaining, magnet S1E1 referred to. It has alaminated core or frame and may have as in Fig. 3, a single winding S10,or a number of windings S11m and .S100 on sepal rate cores, as shown onFig. 4.

S20 is the armature of the magnet S1s and is mounted on the pivot S21 sothat its lower end may swing toward and from the magnet S10. Thearmaturel S20 has a. finger S22 with its free end in contact with thelower end of the reduced extension of the plunger S1. The material ofthe armature is distributed so that, if free to act, its lower end willswing toward the magnet S12. If both coils are denergized, the weight ofthe plunger S7 and the parts supported thereby causes the armature yS20to move into the position shown in the drawing. When in this position,the magnet S10 cannot'pull the armature S20 across the wide air-gapbetween itseif and the adjacent poles of the magnetv and thereby operatethe switch; but when the switch is operated by the 'winding S8,

' the armature S20 swings by gravity toward the magnet-Suthe :finger S22following the lower end of the plunger S1. When .the ar mature S20 has,moved so as to reduce the said air-gapr sufiiciently, it will be actedupon `by the magnet S12V with sufficient force to hold the switchcontact plate S10 against the said contact brushes; and the winding Ssmay, therefore, be denergized as soon as the vcontact brushes.

In order that the force exerted by they magnet S12 on the armature S20may be much less than that required between the contact lplate S10 andthe contact brushes S11 I have constructed the parts so that thedistance from the fulcruiii or pivot S21 o'f the armature S20 to thelower end thereof which is acted upon by the magnet S12 is greater thanlthe distance from the said fulcrurn or pivot to the upper end of thearmature on which the lower -end of the plunger S7 rests. By thisarrangement I can use a comparatively small holding magnet which ischeap to construct. The power required to hold the switch closed is alsoreduced to a minimum.- p

In Fig. 3, I have shown the magnet S18' with a single coil S19 to be'connected across one pair of the primary mains; and in Fig. -1 I haveshown'the magnet S181 with'two coils S101 and S120, which maybeconnected across two diiicrent pairs of the pri-mary mains,thereby'forming a polyphase magnet exerting at all times' anattraction-on th armature S20 and thereby reducing th chatter or noiseto a minimum.

Referring now to the wiring diagram of plate S10 has engaged the M areenergized by closing the switch K.v

The secondary wires 5, 6, 7 have resistance's 8 to 16 arranged to beshort-circuited in groups by the closure of switches S2, Sb,

S0, vconstructed as shown in Figs. land 2.

When the main switch K is closed, current Hows in the primary wires 1,2, and 3 and through the'holding windings S12, which are connected inseries across the wires 2v and 3. Current in the Secondary wires 5, 6,

and 7 is controlled by the resistances 8 tol 16. The first rush ofcurrent in the winding Sa of the switch S2, which' is connected acrossthe resistances 9 and 10, will bevsutcient to lock the switch S open..fr'lhe switch S1 remains locked open until the'c'ure rent in its windingdecreases to a point at which the switch is adjusted to operate, at

which time it will close its contacts and short-circuit the resistances8",`9,"a`iid, 10 and its operating winding S2. The winding S19 below theswitch holds the llatter closed. The closure of the switch S also causestheA winding S8 of'theswitch S0 to be energized..

The increased amount of current in the'seclondary circuit due to thecutting out of thel resistances 8, 9, -and 10 causes the switchv S0 tobe locked open until the current in its winding drops to a predeterminedvalue, at which time the switch S1 closes, short-circuiting theresistances 11, 12, and 13 and the winding S0 oi the switch S1 whichremains closed due to its holding coil S10. The closure of the switchSbcauses thewinding Si of the switch S"l to receive current. This switchis then locked open by the-increase of current in the secondary circuit.When; Athe current again decreases toa predetermined valuc the switch Scloses, short-circuiting the remaining group of resistances 14, 15, and16 and its own operating wind ing S0, the switch being then held closedby its holding winding S10. The secondary windings of the motor are nowentirely sliort-circ'uited, and the motor operates at its normal speed.When itis desired to stop the motor the switch K'is opened, which cutsoii' the motor current. The holding windings S10 are also -de'nergizedby the opening of the switch K, and the switches S, S, S2 drop open.Since the resistance controlling switches cannot open until the mainswitch K is opened, the contacts of the switches S1, S1', Sc donot-carry current at the time y the switches open, inakingit unnecessaryto:`

provide blow-clit magnets or other devices for extinguishing arcs. Ihave shown Vthev actuating windings of the threefacceleratlng switchesconnected in different phases, .but it-is obvious that they can all beconnected in the saine phase without altering the principles oiA thesystem described. I have shown the holding magnets in Fig. 5 as be isc`ing single-phase magnets connected in seing S19", there is always aresultant mag' lns Correction in LettersPatentNio.1,134,422

ries, but it will he readily understood that they may be connected inparallel.

In Figs. 6 and e?, I have shown the holding win ings on each switcharranged to be excited on more than one pair of leads, each holdingmagnet having two windings Sme` and S19". l These windings may beconnected 1n parallehas shown in Fig. 6, or in series, as shown in Fig.7. Since the current in one windingS19a of a holding magnet is out y 1of phase with the current in the other windnetization which prevents thechattering of the switch parts.

In the type of motor shown where resistances are used in the secondarycircuit of th motor to vary its speed, the windings receiving energyfrom the secondary circuit ef the motor are subjected to a currentWhosel fre- ?uency gradually diminishes. `When the4 requency becomesvery low the time between maximum magnetization in one direction and themaximum magnetization in the other direction is so, great that, in thevcase of` a switch, the svritchvould open and 'close its contacts instep with the frequency. By placing the-maintaining windings in theprimary circuit where the windings are subjected to a current'ofsubstantially constant frequency, the switch would remain closed.Although I have shown these magnetic devices arranged to control thestarting of an alternating current motor, I wish it to be understoodthat these devices can be used in various ways' in electric circuitsinwhich an operating 'magnet maybe denergized, its holding functionbeing transferred to a holding magnet. r

My'invention can be applied tomagneti- .cally-operated devices of manyforms, such as a device for operating electric brakes in [snAn l whichit becomes necessary to laminate the comparatively small holding magnetonly which is energized while the apparatus is in service.

Although I have shown my invention api' plied to a three-phase system,it will be understood thatl it can be readily adapted for use in asinglelphase or any plyphase 5a ward its closed position, andelectro-magnet, and a lever biased to move a portion thereof toward theelectro-magnet, the lever having a portion acted on by the lsaid switchmember when in its initial position to prevent the lever from. operatingunder its bias, and the t0 lever having operated under its bias beingattracted and held by the electro-magnet to prevent the return of theswitch member to its initial position.

2. In a switch, a movable switch-operati t5 ing member, an operatingwinding therefor in the circuit. controlled by the switch, the c'ontatsof the switch beingarranged when closed to denergize the winding, asecond winding, and an armature therefor normally 79 beyond but biasedtoward the eiifective influence of the second winding, and restrained bythe movable member while in its initial position from movement into theinuence of the second winding, a portion of the' 75 armature beingarranged tohold the switch member closed'whenpthe armature is held bythe second winding.

Signed at Cleveland, Ohio, this 25th day of July, A. D. 1911. 4 HARRY F.STRTTON. lVitnesses:

H. M. Drnivrnn, J. H. HALL.

It is hereby certified that in Letters Patent No. 1,134,42'2, grantedpril 6, 1915, upon the application ot Harry F. Stratton, of Cleveland,Ohio, for an improvement in Electric Switches, an error appears in theprintedspecitication requiring correctidn as follows: Page 3, line 55for the `word and read afa; and that the said Letters Patent should beread with this correction therein that the same may conform` to therecord 'ot the case in the Patent liiee.

Sig-ned and sealed this ith day of May, A. D., 1915.

n. r. wniTEHAn,

Actng Commissioner of Patents.

